--- title: "Artificial Selection — AP Enviro Definition & Exam Guide" description: "Artificial selection is how pests evolve resistance to pesticides over generations. Learn how it drives the pesticide treadmill and shows up on the AP Enviro exam." canonical: "https://fiveable.me/ap-enviro/key-terms/artificial-selection" type: "key-term" subject: "AP Environmental Science" unit: "Unit 5" --- # Artificial Selection — AP Enviro Definition & Exam Guide ## Definition In AP Environmental Science, artificial selection is the process where repeated pesticide use kills off susceptible pests but lets resistant individuals survive and reproduce, so each generation becomes more resistant to the chemical. ## What It Is Artificial selection is what happens when humans accidentally breed super-pests. When you spray an insecticide, it wipes out most of the target population, but a few individuals happen to carry genes that let them survive. Those survivors reproduce, and they pass that [resistance](/ap-enviro/unit-5/pest-control-methods/study-guide/dXLmUIL3KlkvJHKqr02Z "fv-autolink") on. Spray again next [season](/ap-enviro/unit-4/solar-radiation-earths-seasons/study-guide/LCpdCQ0PbLUZc0WOrqjG "fv-autolink") and you're left with an even higher fraction of resistant bugs. Do this for five or six growing seasons and the chemical barely works anymore. The AP CED ties this directly to pest control. EK EIN-2.G.1 says that organisms can become resistant to [pesticides](/ap-enviro/unit-5/integrated-pest-management/study-guide/qT1rsJ89dPMIyQHRaWz4 "fv-autolink"), herbicides, fungicides, rodenticides, and insecticides through artificial selection. The word "artificial" matters: nature isn't choosing the survivors, humans are, by repeatedly applying the same chemical pressure. It's the exact same logic as natural selection, just with a person holding the sprayer instead of the environment doing the filtering. ## Why It Matters This term lives in [Unit 5](/ap-enviro/unit-5 "fv-autolink"): Land and Water Use, specifically Topic 5.6 Pest Control Methods, and it supports learning objective [AP Enviro](/ap-enviro "fv-autolink") 5.6.A (describe the benefits and drawbacks of different methods of pest control). It's the classic "drawback" half of that objective. Pesticides genuinely cut crop damage and boost crop yields, which is the benefit. But artificial selection is the catch: the more you rely on a chemical, the faster it stops working. That benefit-versus-drawback tension is exactly what the exam wants you to weigh. ## Connections ### [Pesticide Treadmill (Unit 5)](/ap-enviro/key-terms/pesticide-treadmill) Artificial selection is the engine that powers the [pesticide treadmill](/ap-enviro/key-terms/pesticide-treadmill "fv-autolink"). As resistant pests survive and multiply, you need more pesticide, stronger pesticide, or new chemicals just to get the same kill rate, so you're stuck running in place spending more for less. ### [Genetically Engineered Crops (Unit 5)](/ap-enviro/key-terms/genetically-engineered-crops) EK EIN-2.G.2 offers GE crops as one alternative to chemical spraying, engineering pest resistance right into the plant. But it has its own drawback: relying on a single engineered variety can erase a crop's [genetic diversity](/ap-enviro/key-terms/genetic-diversity "fv-autolink"), which leaves it vulnerable to a single new disease. ### [Genetic Resistance (Unit 5)](/ap-enviro/key-terms/genetic-resistance) [Genetic resistance](/ap-enviro/key-terms/genetic-resistance "fv-autolink") is the trait artificial selection is selecting for. A pest can't 'decide' to become resistant; the resistance genes have to already exist in a few individuals, and the pesticide just removes everyone who lacks them. ## On the AP Exam Expect this on multiple-choice questions as a scenario, not a vocab term you simply define. A typical stem describes a farmer who sprayed the same insecticide for five seasons and saw the kill rate drop from 90% to 30%; you have to recognize that artificial selection produced a resistant aphid population. On an FRQ, you'd use it to explain a drawback of pesticide use or to justify why an integrated or rotated pest-control approach works better. The move you need to make: connect repeated chemical use to evolved resistance, and then explain the consequence (lower effectiveness, the need for more or different chemicals). ## artificial selection vs natural selection The mechanism is identical, both are survival and reproduction of the best-adapted individuals. The difference is who applies the pressure. In natural selection the environment does the filtering; in artificial selection a human does, here by repeatedly spraying a pesticide. On the AP exam, pest resistance counts as artificial selection because human spraying is the selective force. ## Key Takeaways - Artificial selection is how repeated pesticide use breeds resistant pest populations, because survivors with resistance genes reproduce while susceptible individuals die off. - It's the main drawback of chemical pest control under learning objective AP Enviro 5.6.A, balanced against the benefit of higher crop yields. - The pesticide stops working over generations because each round of spraying increases the fraction of resistant individuals in the population. - Artificial selection drives the pesticide treadmill, forcing farmers to use more or stronger chemicals over time. - It uses the same logic as natural selection, but humans (not the environment) are the selective pressure. ## FAQs ### What is artificial selection in the context of pest control? It's the process where repeatedly applying a pesticide kills susceptible pests but lets resistant individuals survive and reproduce, so each generation becomes more resistant. EK EIN-2.G.1 names it directly as a consequence of using pesticides, herbicides, fungicides, rodenticides, and insecticides. ### Are pests intentionally evolving to resist pesticides? No. The pests aren't choosing to become resistant. The resistance genes already exist in a few individuals, and spraying simply removes everyone who lacks them, leaving the resistant ones to breed. ### How is artificial selection different from natural selection? The mechanism is the same, but the selective pressure differs. In natural selection the environment determines who survives; in artificial selection a human does, in this case by spraying a pesticide that filters the population. ### Why does a pesticide stop working after several seasons? Because of artificial selection. A practice scenario shows a farmer dropping from a 90% kill rate to 30% over five seasons, since the resistant aphids that survive each spraying keep reproducing until they dominate the population. ### How do genetically engineered crops relate to artificial selection? GE crops (EK EIN-2.G.2) are an alternative that builds pest resistance into the plant instead of relying on chemicals. But they carry their own drawback, since planting one engineered variety widely can reduce the crop's genetic diversity. ## Related Study Guides - [5.6 Pest Control Methods](/ap-enviro/unit-5/pest-control-methods/study-guide/dXLmUIL3KlkvJHKqr02Z) ## Structured Data ```json {"@context":"https://schema.org","@graph":[{"@type":"LearningResource","@id":"https://fiveable.me/ap-enviro/key-terms/artificial-selection#resource","name":"Artificial Selection — AP Enviro Definition & Exam Guide","url":"https://fiveable.me/ap-enviro/key-terms/artificial-selection","learningResourceType":"Concept explainer","educationalLevel":"AP® / High School","about":{"@id":"https://fiveable.me/ap-enviro/key-terms/artificial-selection#term"},"audience":{"@type":"EducationalAudience","educationalRole":"student"},"dateModified":"2026-06-11T05:58:33.365Z","isPartOf":{"@type":"Collection","name":"AP Environmental Science Key Terms","url":"https://fiveable.me/ap-enviro/key-terms"},"publisher":{"@type":"Organization","name":"Fiveable","url":"https://fiveable.me"}},{"@type":"DefinedTerm","@id":"https://fiveable.me/ap-enviro/key-terms/artificial-selection#term","name":"artificial selection","description":"In AP Environmental Science, artificial selection is the process where repeated pesticide use kills off susceptible pests but lets resistant individuals survive and reproduce, so each generation becomes more resistant to the chemical.","url":"https://fiveable.me/ap-enviro/key-terms/artificial-selection","inDefinedTermSet":{"@type":"DefinedTermSet","name":"AP Environmental Science Key Terms","url":"https://fiveable.me/ap-enviro/key-terms"}},{"@type":"FAQPage","mainEntity":[{"@type":"Question","name":"What is artificial selection in the context of pest control?","acceptedAnswer":{"@type":"Answer","text":"It's the process where repeatedly applying a pesticide kills susceptible pests but lets resistant individuals survive and reproduce, so each generation becomes more resistant. 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